Efficacy of blood plasma spectroscopy for early liver cancer diagnostics in obese patients.

INTRODUCTION AND OBJECTIVES: Hepatocellular carcinoma (HCC) represents one of the most common cancers worldwide. A considerable proportion of HCC is caused by cirrhosis related to metabolic dysfunction-associated steatohepatitis (MASH). Due to the increasing prevalence of metabolic syndrome, it is estimated that MASH-related HCC will become the most prevalent etiology of HCC. Currently, HCC screening is based on liver ultrasonography; however, the sensitivity of ultrasonography for early HCC stages in obese patients only reaches 23 %. To date, no studied biomarker shows sufficient efficacy for screening purposes. Nevertheless, the usage of spectroscopic methods offers a new perspective, as its potential use would provide cheap, fast analysis of samples such as blood plasma. MATERIAL AND METHODS: We employed a combination of conventional and chiroptical spectroscopic methods to study differences between the blood plasma of obese cirrhotic patients with and without HCC. We included 20 subjects with HCC and 17 without evidence of liver cancer, all of them with body mass index ≥ 30. RESULTS: Sensitivities and specificities reached values as follows: 0.780 and 0.905 for infrared spectroscopy, 0.700 and 0.767 for Raman spectroscopy, 0.840 and 0.743 for electronic circular dichroism, and 0.805 and 0.923 for Raman optical activity. The final combined classification model based on all spectroscopic methods reached a sensitivity of 0.810 and a specificity of 0.857, with the highest area under the receiver operating characteristic curve among all models (0.961). CONCLUSIONS: We suggest that this approach can be used effectively as a diagnostic tool in patients who are not examinable by liver ultrasonography. CLINICAL TRIAL REGISTRATION: NCT04221347.

Invasive measurement of hepatic venous pressure gradient before resection of hepatocellular carcinoma.

Aim of the study: To evaluate the role of hepatic venous pressure gradient (HVPG) measurement in patients with resectable hepatocellular carcinoma (HCC) we describe our experience with the procedure as part of our hospital standard preoperative algorithm. We present our protocol for this situation, the HVPG measurement procedure, and the results of our cohort. Material and methods: We performed a retrospective statistical analysis of all patients who underwent planned hepatic resection for HCC with HVPG measurement between 1/2016 and 1/2023. The cohort included 35 patients (30 males, mean age 69.5 years) who underwent HVPG measurement before liver resection for HCC. Results: The success rate of measurement was 91.4%, with serious complications in 2.9% of cases. Due to the clinically significant portal hypertension (CSPH) 31.3% of patients were rejected for resection. Seventeen patients with excluded CSPH underwent resection with one case of a postoperative liver event, liver decompensation, representing 5.9% of them. One patient (5.9%) had a complicated postoperative course with fasciitis. None of the patients who underwent resection (88.2%) was readmitted to the hospital due to surgical complications or a liver event during 90 days of follow-up, and no death was reported. The median overall survival (OS) in the resected subgroup was 70 months (95% CI: 52-86), and in patients rejected for surgery (resection and transplantation) 35 months (95% CI: 13-48). Conclusions: HVPG measurement is the gold standard for the quantification of portal hypertension. Hepatic vein catheterization is invasive, but a safe procedure, with a clear impact on the management of resectable HCC.

Chemotherapy versus chemoradiotherapy in borderline resectable and locally advanced pancreatic adenocarcinoma.

The role of radiotherapy in borderline resectable (BRPC) and locally advanced pancreatic carcinoma (LAPC) remains controversial. In our study, we retrospectively evaluated 48 patients with BRPC (14; 29.2%) and LAPC (34; 70. 8%) who underwent 6-8 cycles of induction mFOLFIRINOX chemotherapy alone (23; 47.9%) or 4-6 cycles of mFOLFIRINOX followed by hypofractionated radiotherapy (up to the total dose of 39.9 Gy in 15 fractions) (25; 52.1%). Survival parameters were evaluated using the Gehan-Breslow-Wilcoxon Test and compared by using the long-rank test. The addition of radiotherapy was not associated with better survival (16.9 months for chemotherapy only versus 15.9 months for the combined therapy; p=0.486), as well as for both subgroups (13.5 months vs. 18.3 months; p=0.679) and (20.7 months vs. 13.8 months; p=0.425) for BRPC and LAPC, respectively. A higher resection rate was seen in the BRPC group compared to the LAPC group (43% vs. 17.6%, respectively). Our study revealed a significantly higher rate of lung metastases in patients after the combination therapy compared to those treated by chemotherapy only (19% vs. 0%, respectively; p=0.045). Such a borderline result, however, prevents us from drawing clear conclusions about whether this is an artifact caused by the low number of patients or whether radiotherapy leads to a selection of stem cells with a predilection to the generalization to the lungs.

Etiopathogenetic Factors of Hepatocellular Carcinoma, Overall Survival, and Their Evolution over Time-Czech Tertiary Center Overview.

Background and Objectives: Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer with a highly unfavorable prognosis. Aims: Retrospective statistical analysis of patients with HCC in the field of liver cirrhosis treated at our center from the perspective of demography, and the effects of key changes in diagnostic and therapeutic procedures in the last 10 years on overall survival (OS) and earlier diagnosis. Materials and Methods: This study included 170 cirrhotic patients with HCC (136 men, 80%). Demographic and etiological factors and OS were analyzed based on distribution into three groups according to the period and key changes in diagnostic and therapeutic approaches (BCLC classification staging; standardization of protocol for transarterial chemoembolization (TACE) and the introduction of direct-acting antivirals (DAA) for the treatment of chronic viral hepatitis C (HCV); expansion of systemic oncological therapy). Results: The mean age at the time of diagnosis was 69.3 years (SD = 8.1), and etiology was as follows: non-alcoholic steatohepatitis (NASH) 39%, alcoholic liver disease (ALD) 36%, HCV 18%, cryptogenic liver cirrhosis 3%, chronic hepatitis B infection (HBV) 2%, and other etiology 2%. Distribution of stages according to the BCLC: 0 + A 36%, B 31%, C 22%, and D 11%. However, the distribution in the first studied period was as follows: 0 + A 15%, B 34%, C 36%, and D 15%; and in the last period: 0 + A 45%, B 27%, C 17%, and D 11%, and difference was statistically significant (p < 0.05). The median OS for stages 0 + A, B, C, and D was 58, 19, 6, and 2 months, respectively. During the monitored period, there was a visible increase in the etiology of ALD from 30% to 47% and a decrease in HCV from 22% to 11%. In patients treated with TACE (stage B), the median OS grew from 10 to 24 months (p < 0.0001) between the marginal monitored periods. Conclusions: We described a decreasing number of patients with HCV-related HCC during follow-up possibly linked with the introduction of DAA. In our cohort, an improvement in early-stage diagnosis was found, which we mainly concluded as a result of proper ultrasound surveillance, the institution of a HCV treatment center, and increased experience of our sonographers with an examination of cirrhotic patients. Lastly, we described significantly improved overall survival in patients with intermediate HCC treated by TACE, due to the increased experience of interventional radiologists with the method at our facility and an earlier switch to systemic therapy in case of non-response to TACE.

Differential diagnosis of pituitary enlargement.

Enlargement of the pituitary gland is heterogenous in the etiology. Common causes of pituitary enlargement are physiological hypertrophy during pregnancy, primary and secondary tumors, autoimmune hypophysitis including side effects of anticancer therapy with check-point inhibitors. Terms like hypertrophy, hyperplasia, sellar expansion and hypophysitis are commonly used to describe enlargement of the pituitary gland on MR scan regardless its etiology. The most common pathology causing pituitary gland enlargement is pituitary adenoma. Magnetic resonance imaging can differentiate pituitary tumors from diffuse enlargement due to hypophysitis in most but not all cases. Changes on imaging during time or response to pharmacotherapy might help determine the final diagnosis in uncertain cases. We present a case report of a young woman with sellar expansion due to prolonged untreated peripheral hypothyroidism mimicking pituitary adenoma. Interdisciplinary cooperation of endocrinologist, radiologist and neurosurgeon is crucial in determining the diagnosis.

Neuromorphic computing with multi-memristive synapses.

Neuromorphic computing has emerged as a promising avenue towards building the next generation of intelligent computing systems. It has been proposed that memristive devices, which exhibit history-dependent conductivity modulation, could efficiently represent the synaptic weights in artificial neural networks. However, precise modulation of the device conductance over a wide dynamic range, necessary to maintain high network accuracy, is proving to be challenging. To address this, we present a multi-memristive synaptic architecture with an efficient global counter-based arbitration scheme. We focus on phase change memory devices, develop a comprehensive model and demonstrate via simulations the effectiveness of the concept for both spiking and non-spiking neural networks. Moreover, we present experimental results involving over a million phase change memory devices for unsupervised learning of temporal correlations using a spiking neural network. The work presents a significant step towards the realization of large-scale and energy-efficient neuromorphic computing systems.

Temporal correlation detection using computational phase-change memory.

Conventional computers based on the von Neumann architecture perform computation by repeatedly transferring data between their physically separated processing and memory units. As computation becomes increasingly data centric and the scalability limits in terms of performance and power are being reached, alternative computing paradigms with collocated computation and storage are actively being sought. A fascinating such approach is that of computational memory where the physics of nanoscale memory devices are used to perform certain computational tasks within the memory unit in a non-von Neumann manner. We present an experimental demonstration using one million phase change memory devices organized to perform a high-level computational primitive by exploiting the crystallization dynamics. Its result is imprinted in the conductance states of the memory devices. The results of using such a computational memory for processing real-world data sets show that this co-existence of computation and storage at the nanometer scale could enable ultra-dense, low-power, and massively-parallel computing systems.

All-memristive neuromorphic computing with level-tuned neurons.

In the new era of cognitive computing, systems will be able to learn and interact with the environment in ways that will drastically enhance the capabilities of current processors, especially in extracting knowledge from vast amount of data obtained from many sources. Brain-inspired neuromorphic computing systems increasingly attract research interest as an alternative to the classical von Neumann processor architecture, mainly because of the coexistence of memory and processing units. In these systems, the basic components are neurons interconnected by synapses. The neurons, based on their nonlinear dynamics, generate spikes that provide the main communication mechanism. The computational tasks are distributed across the neural network, where synapses implement both the memory and the computational units, by means of learning mechanisms such as spike-timing-dependent plasticity. In this work, we present an all-memristive neuromorphic architecture comprising neurons and synapses realized by using the physical properties and state dynamics of phase-change memristors. The architecture employs a novel concept of interconnecting the neurons in the same layer, resulting in level-tuned neuronal characteristics that preferentially process input information. We demonstrate the proposed architecture in the tasks of unsupervised learning and detection of multiple temporal correlations in parallel input streams. The efficiency of the neuromorphic architecture along with the homogenous neuro-synaptic dynamics implemented with nanoscale phase-change memristors represent a significant step towards the development of ultrahigh-density neuromorphic co-processors.

Stochastic phase-change neurons.

Artificial neuromorphic systems based on populations of spiking neurons are an indispensable tool in understanding the human brain and in constructing neuromimetic computational systems. To reach areal and power efficiencies comparable to those seen in biological systems, electroionics-based and phase-change-based memristive devices have been explored as nanoscale counterparts of synapses. However, progress on scalable realizations of neurons has so far been limited. Here, we show that chalcogenide-based phase-change materials can be used to create an artificial neuron in which the membrane potential is represented by the phase configuration of the nanoscale phase-change device. By exploiting the physics of reversible amorphous-to-crystal phase transitions, we show that the temporal integration of postsynaptic potentials can be achieved on a nanosecond timescale. Moreover, we show that this is inherently stochastic because of the melt-quench-induced reconfiguration of the atomic structure occurring when the neuron is reset. We demonstrate the use of these phase-change neurons, and their populations, in the detection of temporal correlations in parallel data streams and in sub-Nyquist representation of high-bandwidth signals.

A high-bandwidth spintronic position sensor.

Position sensing with resolution down to the scale of a single atom is of key importance in nanoscale science and engineering. However, only optical-sensing methods are currently capable of non-contact sensing at such resolution over a high bandwidth. Here, we report a new non-contact, non-optical position-sensing concept based on detecting changes in a high-gradient magnetic field of a microscale magnetic dipole by means of spintronic sensors. Experimental measurements show a sensitivity of up to 40 Ω/µm, a linear range greater than 10 µm and a noise floor of 0.5 pm/√[Hz]. Also shown is the use of the sensor for position measurements for closed-loop control of a high-speed atomic force microscope with a frame rate of more than 1 frame/s.

High-speed multiresolution scanning probe microscopy based on Lissajous scan trajectories.

A novel scan trajectory for high-speed scanning probe microscopy is presented in which the probe follows a two-dimensional Lissajous pattern. The Lissajous pattern is generated by actuating the scanner with two single-tone harmonic waveforms of constant frequency and amplitude. Owing to the extremely narrow frequency spectrum, high imaging speeds can be achieved without exciting the unwanted resonant modes of the scanner and without increasing the sensitivity of the feedback loop to the measurement noise. The trajectory also enables rapid multiresolution imaging, providing a preview of the scanned area in a fraction of the overall scan time. We present a procedure for tuning the spatial and the temporal resolution of Lissajous trajectories and show experimental results obtained on a custom-built atomic force microscope (AFM). Real-time AFM imaging with a frame rate of 1 frame s⁻¹ is demonstrated.

Impulsive control for fast nanopositioning.

In this paper we present a non-linear control scheme for high-speed nanopositioning based on impulsive control. Unlike in the case of a linear feedback controller, the controller states are altered in a discontinuous manner at specific instances in time. Using this technique, it is possible to simultaneously achieve good tracking performance, disturbance rejection and tolerance to measurement noise. Impulsive control is demonstrated experimentally on an atomic force microscope. A significant improvement in tracking performance is demonstrated.